3/28/21 Bulky Uterus : What’s beyond Disclosure fibroids? The authors have no disclosure of funding received Shweta Bhatt, MD for this work from any organizations. Professor of Radiology Mayo Clinic, Jacksonville, Florida Introduction/Objectives Normal Physiologic Appearance of the Uterus Woman of childbearing age: • Average length x width = 8.0 x 5.0 cm • Menstrual phase: • Endometrial thickness < 4mm Introduction: • Ill-defined myometrium with poor definition of the Junctional zone • The uterus is a dynamic organ that varies in appearance throughout a woman’s life. A • Proliferative phase: • Endometrial thickness 4-8 mm thorough understanding of its response to hormonal fluctuations and pregnancy is • Well defined zonal anatomy of endometrium, Junctional zone, and myometrium necessary for distinguishing between normal variation and abnormal enlargement. • Secretory phase: Additionally, a multitude of neoplastic processes can cause diffuse or focal enlargement, • Endometrial thickness 8-16 mm • making the diagnostic process quite challenging. Increasing thickness of the endometrium and myometrium with well defined zonal anatomy Postmenopausal woman: Objectives: • Average length x width = 5.0 x 2.0 cm • • Endometrial thickness <5mm Review the normal physiologic variation in size and appearance of the uterus • Myometrium becomes isointense with Junctional zone • Review the normal physiologic appearance of the postpartum uterus • Review the most common causes of uterine enlargement • Discuss their imaging appearance across multiple modalities with a focus on ultrasound and MRI • This educational exhibit is intended for the general radiologist or radiology resident Menstrual Proliferative Secretory Postmenopausal Causes of Uterine Enlargement Physiologic Enlargement: Hormonal Causes Physiologic Peripartum Anatomic Vascular Neoplastic Abnormal physiologic enlargement of the uterus is most commonly due to excess circulating estrogen/progesterone from either exogenous or endogenous Pelvic Congestion Myometrial Hormonal Delay of Involution Adenomyosis Syndrome Neoplasm sources • Exogenous causes (Common): Retained Arteriovenous • Tamoxifen (See next slide) Myometrial Placenta/Products Malformation Endometrial Contraction Cervical Stenosis Neoplasm of Conception (AVM) • Oral contraceptives • Typically combination of estrogen and progesterone Mullerian Duct Cervical • Most common imaging findings: Endometritis abnormalities Neoplasm • Globular enlargement of the myometrium • Atrophy of the endometrium Gestational Gestational Trophoblastic Trophoblastic Neoplasm Neoplasm • Endogenous causes (Rare): • Hormone producing adnexal tumor • Similar imaging findings as Tamoxifen from estrogen or gonadotropin Lymphoma producing effects Metastases 1 3/28/21 Physiologic Enlargement: Physiologic Enlargement: Tamoxifen related changes Myometrial Contraction • Contraction of the endometrial/subendometrial complex producing a mass-like Tamoxifen related changes: A - Pro-estrogen effects on the uterus convexity into the endometrial canal - Causes spectrum of changes including: • Does not deform the outer uterine contour - Endometrial Polyp (Most common) • Transient: Resolves within 45 minutes - Endometrial Hyperplasia • Best seen with cine MRI although can be seen between multiple acquisitions - Cystic Atrophy over the course of a non-cine MRI - Endometrial Carcinoma - Adenomyosis Most Common Ultrasound Features: Sagittal grayscale ultrasound image demonstrates - Hyperechoic endometrial thickening (≥ 8mm) with hyperechoic endometrial thickening with cystic spaces multiple irregular cystic spaces B Most Common MRI Features: - T1WI: Isointense endometrial thickening - T2WI: Heterogeneous endometrial thickening +/- endometrial/subendometrial cysts Best Diagnostic clue: - Clinical history of a breast cancer patient on Tamoxifen Sagittal T2WI demonstrates heterogeneous signal Most common presentation: throughout a widened endometrium with multiple - Irregular endometrial thickening with cystic spaces subendometrial cysts Sagittal T2WI Sagittal T2WI fat suppressed obtained 25 minutes later Normal Postpartum Appearance Peripartum Enlargement: Imaging Findings: • Endometrium: A Delay of Involution • Heterogeneous in appearance • Ultrasound: Endometrial canal filled with hypoechoic material Definition: A (fluid) and echogenic material (hemorrhage) - Delay in the expected decrease in size of the postpartum uterus • MRI: Endometrial canal filled with high T2 signal (fluid) and low T2 signal (hemorrhage) • Myometrium: Clinical Presentation: • Enlarged and typically of lower echogenicity (US)/higher T2 - Most commonly presents with abnormal postpartum bleeding signal (MRI) consistent with edematous changes. • Junctional zone: Imaging Findings: • Ill defined up to 6 weeks postpartum - Uterus larger than expected given time passed since delivery B - Persistence of fluid/hemorrhage in the endometrial canal Size: - Persistence of myometrial engorgement/edema B • The postpartum uterus gradually decreases in size over several weeks with the greatest decrease occurring during the 1st week Potential causes including: Mean Uterine Length Postpartum (cm) - Endometrial hematoma - Endometritis 15 13.8 - Retained products of conception 10.2 - Gestational trophoblastic neoplasm 10 8.6 6.1 - Leiomyomas - Uterine anomalies 5 Axial (A) and Sagittal (B) T2 fat suppressed MRI images in a patient 3 days post vaginal delivery. The Axial T1WI (A) and T2 fat suppressed (B) MRI 0 myometrium is diffusely enlarged with heterogeneous images in a patient 3 weeks postpartum. The signal and cystic changes. The junctional zone is poorly uterus demonstrates persistent enlargement as 30 hrs 1 we ek 2 we eks 6 we eks defined. There is also low signal in the endometrial well as high T2 signal throughout the myometrium. canal consistent with hemorrhage (red arrow). D+C revealed endometrial hematoma Peripartum Enlargement: Endometritis Peripartum Enlargement: Retained Products of Conception Clinical Presentation: A - Fever and pelvic tenderness in a postpartum patient A - More common in complicated pregnancies (Premature rupture of membranes, prolonged labor, retained products, etc.) Clinical Presentation: - Pain and bleeding after a recent miscarriage, abortion, or delivery Imaging Findings: - Elevated hCG - Endometritis is a clinical diagnosis and imaging findings are frequently normal Imaging Findings: - CT is the most common modality ordered to assess for alternative - Ultrasound: Endometrial mass of heterogeneous echotexture with explanation of postpartum fever positive vascularity - Most common finding includes endometrial thickening with - CT/MRI: Heterogeneous endometrial mass with variable fluid/gas in the endometrial cavity enhancement B - Caveats: B - Thinning of the myometrium on any modality suggests mal- - Uncomplicated endometritis may have normal imaging implantation of the placenta (ie: placenta accreta, increta, percreta) findings - Gas in the endometrial cavity can be a normal finding Key differential diagnoses in a postpartum patient: within the first 3 weeks postpartum - Endometrial hematoma: No appreciable vascularity/enhancement - Serial exams may be helpful for distinguishing endometritis from - Gestational trophoblastic neoplasm: Markedly elevated hCG normal postpartum fluid/gas Best Diagnostic Clue: - Clinical history of fever and pelvic tenderness in a postpartum Sagittal (A) and axial (B) CECT in a patient 5 days post C-section demonstrates Sagittal T2WI (A) and T1+C (B) MRI images in a patient patient post abortion with a hCG 51 - Fluid and gas in the endometrial cavity thickened endometrium with fluid and gas demonstrates a heterogeneous endometrial in the endometrial cavity mass with avid contrast enhancement. 2 3/28/21 Peripartum Enlargement: Peripartum Enlargement: Gestational Trophoblastic Neoplasm Gestational Trophoblastic Neoplasm Background: A B • Comprises a spectrum of premalignant and malignant placental lesions • Premalignant lesions: Complete hydatidiform mole (CHM), Partial hydatidiform mole(PHM) • CHM: 46XX diploid, usually no fetal tissue present unless dizygotic twin pregnancy • PHM: Triploid, fetus/embryo present • Malignant lesions: Invasive mole, choriocarcinoma, placental site trophoblastic tumor (PSTT) • Invasive mole: A CHM or PHM that has invaded the myometrium • Choriocarcinoma: Abnormal proliferation of trophoblastic tissue that has often invaded myometrium and metastasized at time of diagnosis • PSTT: Focal neoplastic proliferation of trophoblasts in the myometrium at the site of placental insertion C D Imaging Findings: • GTN typically discovered as an absent/abnormal intrauterine pregnancy on prenatal ultrasound • CT/MRI can be used as follow up studies to assess for myometrial invasion or metastatic disease • CHM: Cystic endometrial mass with no associated embryo/fetus • PHM: Enlarged cystic placenta associated with an abnormal fetus • Invasive mole: Heterogeneous cystic endometrial mass invading into the myometrium • Choriocarcinoma: Heterogeneous echogenic mass with marked vascularity, often metastatic at time of diagnosis • PSTT: Heterogeneous echogenic mass with little vascularity. Can have cystic spaces like CHM/PHM. Key point: Sagittal grayscale (A) and color doppler (B) images in a patient 10 weeks from her last menstrual period - No reliable way to distinguish CHM, PHM, or miscarriage on imaging. Role of imaging is to identify abnormal with hCG 287,395. There is a heterogeneous, primarily isoechoic mass arising from the uterus